In front-end/back-end topologies, front end plays the application role and back end plays the storage role. You can combine up to three application servers to form a cluster and add a fourth server for redundancy. Each cluster supports flexible message stores for each user. Dedicated application servers communicate with the telephony server and the AxC/Directory server that resides on the Avaya message store.
You can design your system with the location of the front-end application servers is remote from the back-end storage server. Due to this flexibility, you can choose either distributed or centralized system topologies for your organization.
Scalability and redundancy are the two reasons to choose a cluster configuration. You can group up to three application servers in a cluster, plus a fourth application server for redundancy. With 100 ports per server at 62 users per port, three servers support 18,600 users. The maximum number of active ports per cluster is 300.
